Caption: Pollen on a bee leg. Coloured scanning electron micrograph (SEM) of pollen grains (green) on the leg of a bee (superfamily Apoidea). Pollen grains are the male sex cells of a flowering plant. They are usually carried to another flower by pollinating insects, such as bees. The pollen is trapped by the dense coating of hairs on the leg. When the pollen rubs off on a flower's female structure (pistil), fertilisation can occur.